Plate-based adsorption chiller subassembly

ABSTRACT

A subassembly for an adsorption chiller includes an adsorption component that includes a plurality of plates arranged in a stack. Refrigerant passages are defined between refrigerant sides of adjacent pairs of the plates in the stack. An adsorbent material is disposed within the refrigerant passages.

SUMMARY

A subassembly for an adsorption chiller comprises an adsorptioncomponent that includes a plurality of plates arranged in a stack.Refrigerant passages are defined between refrigerant sides of adjacentpairs of the plates in the stack. An adsorbent material is disposedwithin the refrigerant passages.

According to some aspects, a subassembly for an adsorption chillercomprises a stack of plates, each plate having an evaporation section,an adsorption section, and a condensation section. The plates arrangedin the stack so that the evaporation sections of the plates form anevaporation unit of the adsorption chiller subassembly, the adsorptionsections of the plates form an adsorption unit of the adsorption chillersubassembly, and the condensation sections of the plates form acondensation unit of the adsorption chiller subassembly.

In some embodiments, a plate for an adsorption chiller subassemblyincludes a refrigerant side and a fluid side, with three sets of flowfeatures on the refrigerant side. A tray feature is disposed between twoof the sets of flow features.

In some embodiments, a plate for an adsorption chiller subassemblyincludes a refrigerant side and a fluid side. The plate includesevaporation, adsorption, and condensation flow fields disposed on thefluid side. A first feature on the fluid side is configured tofluidically decouple the evaporation flow field from the adsorption flowfield. A second feature on the fluid side is configured to fluidicallydecouple the adsorption flow field from the condensation flow field.

A method of forming an adsorption chiller involves attaching anadsorbent on refrigerant sides of plates. The plates having the attachedadsorbent are arranged in a plate stack. The plate stack forms anadsorption unit having a plurality of refrigerant passages, eachrefrigerant passage bounded on by refrigerant sides of the plates.

A method of forming an adsorption chiller involves disposing a brazematerial in, on, and/or about flow features disposed on an exposedsurface of a plate. An adsorbent material is disposed on the brazematerial. The braze material is heated to its liquidus temperature andis then cooled to below its solidus temperature.

The above summary is not intended to describe each embodiment or everyimplementation. A more complete understanding will become apparent andappreciated by referring to the following detailed description andclaims in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram that conceptually illustrates the operation of anadsorption chiller that may be formed according to embodiments discussedherein;

FIG. 2 depicts a type of plate (Plate Type U) that may be used in theevaporation components of an adsorption chiller subassembly inaccordance with various embodiments;

FIG. 3 depicts a type of plate (Plate Type V) that may be used in theevaporation components of an adsorption chiller subassembly inaccordance with various embodiments;

FIG. 4 depicts a type of plate (Plate Type W) that may be used in thecondensation components of an adsorption chiller subassembly inaccordance with various embodiments;

FIG. 5 depicts a type of plate (Plate Type X) that may be used in thecondensation components of an adsorption chiller subassembly inaccordance with various embodiments;

FIGS. 6 and 7 illustrate plates Y and Z that may be used in theadsorbent component of an adsorption chiller subassembly in accordancewith various embodiments;

FIG. 8 conceptually illustrates a see through view of a YZ plate pair;

FIG. 9 shows a side view of an arrangement of plates that form thecondensation, evaporation, and adsorption components of an adsorptionchiller subassembly in accordance with various embodiments;

FIG. 10 shows an arrangement of plates for an adsorption chillersubassembly in accordance with various embodiments;

FIG. 11 conceptually illustrates a possible arrangement of an adsorbentchiller subassembly;

FIGS. 12 and 13 illustrate plates S and T that may be used in theadsorbent component of an adsorption chiller subassembly in accordancewith various embodiments;

FIG. 14 shows a side view of an adsorption chiller arrangement that mayuse the S and T plate in accordance with various embodiments;

FIG. 15 illustrates an exploded view of plates used to form a monolithicadsorption chiller subassembly in accordance with various embodiments;

FIG. 16 depicts the refrigerant side of plate type B that may be used inthe monolithic adsorption chiller subassembly of FIG. 15;

FIG. 17 depicts the fluid side of plate type A may be used in themonolithic adsorption chiller subassembly of FIG. 15;

FIG. 18 shows refrigerant and fluid passages formed between adjacent Aand B plates in the plate stack;

FIG. 19 is a flow diagram illustrating a process of forming aplate-based adsorption chiller subassembly;

FIG. 20 is a flow diagram illustrating a process of brazing anadsorbent, such as silica, to an adsorbent bed in accordance withvarious embodiments;

FIG. 21 is a flow diagram illustrating a process of brazing an adsorbentto the plates and brazing the plates together in accordance with someembodiments;

FIG. 22 is a flow diagram illustrating a process of using a highertemperature braze to braze the adsorbent to the plates and using a lowertemperature braze to braze the plates together in a stack; and

FIG. 23 shows a process for attaching the adsorbent to the plates usinga paste comprising the adsorbent and adhesive or braze.

DESCRIPTION OF VARIOUS EMBODIMENTS

Adsorption chillers utilize thermal energy, e.g., from low-grade wasteheat (˜50-90 C) or water heated by solar energy, to produce usefulcooling. Adsorption chillers operate by adsorption of a refrigerant inan adsorbing material. Adsorbents such as silica gel, activated carbon,and/or zeolites may be used as the adsorbing material and water and/ormethanol may be used as the refrigerant, for example, although otheradsorbent/refrigerant combinations are also possible. The portions ofthe adsorption chiller where vapor is present can be operated at verylow pressures that involve vacuum sealed components. The fluid portionsmay be operated at relatively higher pressures

Some embodiments described herein involve plate-based adsorptionchillers comprising one or more stacks of plates to form evaporation,condensation, and/or adsorbent components of the chiller. FIG. 1 is adiagram that conceptually illustrates the operation of an adsorptionchiller. One or more of the processes discussed in connection with FIG.1 may be implemented in a plate-based adsorption chiller as illustratedin various embodiments described below. The basic processes ofadsorption refrigeration are generally described herein as using wateras the refrigerant and silica gel as the adsorbent, although theembodiments are not limited to any particular adsorbent/refrigerantcombination and various refrigerants and/or adsorbents may be used.

FIG. 1 illustrates the cooling phase and the regeneration phase of anadsorption chiller process. First, consider the cooling phase. Water tobe chilled 111 flows through a heat exchanger 110 in the evaporationcomponent of the adsorption chiller. The water to be chilled 111 iscooled by evaporation of water 120 from a reservoir 130, and exits theheat exchanger 110 as chilled water 112. The cooling phase involves lowpressures, which are sufficiently low to cause the water 120 from thereservoir 130 to boil and evaporate as it contacts the heat exchanger110. Water vapor 121 from the boiling water is adsorbed by an adsorbent140, e.g., silica gel, which is disposed in an adsorbent bed in theadsorbent component of the adsorption chiller. Adsorption of the vapor121 keeps the pressure low so that the evaporation process continues toproduce the chilled water 111. To keep the adsorbent 140 cool duringthis process, water 140, e.g., tepid, cool, or room temperature water(referred to herein as RT water) flows through the heat exchanger 145 ofthe adsorbent component.

Next, consider the regeneration phase. Hot water 151, which provides theenergy input to the chiller, flows through the heat exchanger 145 of theadsorbent component, heating the silica gel 140 and driving off waterfrom the silica gel as water vapor 155. RT water 161 flows through aheat exchanger 160 of the condensation component of the adsorptionchiller. The vapor 155 contacts the heat exchanger 160 and condensesinto water filling the reservoir 130.

In some implementations, the adsorption chiller may use evaporation,condensation, and adsorption components that are arranged in twosubassemblies so that the cooling modes and regeneration modes canproceed substantially simultaneously. For example, consider anadsorption chiller that includes first and second subassemblies. Thefirst subassembly operates in the cooling phase (depicted on the left inFIG. 1) while the second subassembly operated in the regeneration phase(illustrated on the right in FIG. 1). The system can be designed so thatthe silica gel in the first subassembly (on the left in FIG. 1) which isoperating in the cooling phase becomes saturated with the water vapor atabout the same time as the silica gel in the second subassembly (on theright in FIG. 1) operating in the regeneration phase becomes fully dry.The operation of the subassemblies is then reversed, e.g., by switchingvalves (not shown in FIG. 1), to appropriately redirect the refrigerantwater, room temperature water, and heating water. After the switch, thefirst subassembly (on the left in FIG. 1) would operate in theregeneration phase, while the second subassembly (on the right inFIG. 1) would operate in the cooling phase.

Conventional adsorption chillers have used configurations wherein theheat exchangers are disposed within a sealed vacuum vessel (shell) thatallows a low pressure to be achieved within the shell. However, thesevacuum vessels are large, heavy, and expensive. Embodiments discussed inthis disclosure incorporate heat exchangers made of stacked plates,which have flow fields disposed on the plate surfaces to transfer heatbetween fluid sides of the plates and refrigerant sides of the plates toachieve the evaporation, adsorbent, and condensation components of theadsorption chiller. The plates can be aligned in the stack and fluid orrefrigerant flow occurs in the spaces between adjacent plate surfaces.To achieve the low pressures used in adsorption cooling, some or all ofthe adjacent pairs of plates may be gasketed, welded, brazed, and/orotherwise sealed to allow low pressures to the achieved between theplates. The use of stacked plates forms a strong structure capable ofmaintaining sufficiently low pressures for the refrigerant portions ofthe adsorption system.

The use of plate-based adsorption chillers as discussed herein ismaterial efficient; the vast majority of the metal used in constructingthe adsorbent chiller is used to transfer the heat. The materialefficiency of the plate-based systems described in this disclosure maybe contrasted with shell and tube type adsorption chillers wherein theoutermost shell that is used to contain the vacuum makes up a largeportion of the material used in the system, but does not provide anyheat transfer between the fluid and refrigerant in the chiller.

A plate-based adsorption chiller includes a stack of aligned plates. Insome implementations, an adsorbent chiller subassembly includes platesthat form the evaporation component of the chiller, plates that form theadsorbent component of the chiller, and plates that form thecondensation component of the chiller. FIGS. 2 through 8 show exemplaryplates that can be used in a plate-based adsorption chiller subassemblyin accordance with some embodiments.

FIG. 2 depicts a first type of plate (Plate Type U) that may be used inthe evaporation component of an adsorption chiller subassembly. Althoughsimilar plates may be used in the condensation and/or evaporationcomponents of the chiller, the evaporation plates and the condensationplates may have different features, such that the evaporation platesprovide enhanced evaporation functionality and/or the condensation plateprovide enhanced condensation functionality. Plate U, and other platesdiscussed herein may be made of metal, metal alloy, and/or otherthermally conductive materials. Plate Type U includes a first majorsurface 250 and a second major surface 251, as shown in FIG. 2. Featureson the first major surface 250 generally have complementary features onthe second major surface 251. For example, ridges on the first majorsurface 250 may appear as valleys on the second major surface 251 andvice versa.

Plate Type U includes a refrigerant port 210, first and second fluidports 220, 230, and refrigerant port 290. Surface 250 shown in FIG. 2 ison the refrigerant side of plate U. The first and second fluid ports220, 230 include sealing structures 221, 231 that form a seal whencontacting complementary sealing structures on an adjacent plate in thestack, thus preventing the fluid from entering the refrigerant side ofplate U. There are sealing surfaces (not shown) on the second majorsurface 251 of plate U around the refrigerant port 210 and therefrigerant port 290 to prevent the refrigerant from entering the fluidside of plate U. A sealing structure 201 may also be disposed at theperiphery the first major surface 250 which mates to a sealing structureof an adjacent plate.

The surface 250 of the refrigerant side of plate U includes a flow field240 comprising numerous flow features 245, 246. The flow features 245,246 include ridges 245 and valleys 246 that may be formed by stamping,machining, molding, embossing, etching and/or other fabricationprocesses. Note that the ridges 245 on the first major surface 250 willappear as valleys on the second major surface 251 and valleys 246 on thefirst major surface will appear as ridges on the second major surface251. The flow features 245, 246 are depicted in this example as upwardpointing chevrons, however a variety of feature shapes maybe used. Theflow features 245, 246 are configured to direct the flow of fluid acrossthe surfaces 250, 251 and/or to increase heat transfer area and mixingin the fluid flow.

Condensed refrigerant flows from the refrigerant port 290 and evaporateswhen contacting the flow features 245, 246 on the first major surface250 of plate U. The vapor refrigerant exits through the refrigerant port210.

FIG. 3 illustrates a second type of plate (Plate Type V) that can beused in the evaporation component of an adsorbent chiller subassembly.Plate V alternates with plate U in the stack that forms the evaporationcomponent of the adsorbent chiller subassembly. Plate V includes a firstmajor surface 350 and a second major surface 351. Plate V includesrefrigerant port 310, refrigerant port 390, and first and second fluidports 320, 330. A sealing structure 301 is disposed on the periphery ofsurface 350. The sealing structure 301 is configured to mate with asealing structure of an adjacent plate in the stack. Surface 350 is thefluid side of plate V. The refrigerant port 310 and refrigerant port 390include sealing structures 311, 391 at the peripheries of therefrigerant port 310 and refrigerant port 390, respectively. The sealingstructures 311, 391 are configured to mate with complementary sealingstructures at the refrigerant ports of the next plate in the stack toprevent the refrigerant from interacting with fluid side (surface 350)of the plate. Plate V includes a flow field 340 on surface 350 which hasflow features 345, 346 depicted in this example as downward pointingchevrons. Note that flow features 345 and 346 appear as ridges andvalleys, respectively, on surface 350. Complementary flow features (notshown) appear on surface 351.

The U and V plates may alternate in the plate stack so that thedirection of the chevrons of the U plates opposes the direction of thechevrons of the V plates. The upward pointing and downward pointingchevron ridges of the adjacent plates touch in a lattice of contactpoints, creating numerous flow paths which increase the heat transferarea and cause mixing in the flow. Water, e.g., room temperature waterflows across the flow features 345, 346 of surface 350 between fluidports 320, 330.

FIG. 4 depicts a first type of plate (Plate Type W) that may be used inthe condensation component of an adsorption chiller subassembly. PlateType W includes a first major surface 450 and a second major surface451, as shown in FIG. 4. Features on the first major surface 450generally have complementary features on the second major surface 451.For example, ridges on the first major surface 450 may appear as valleys451 on the second major surface and vice versa.

Plate Type W includes a refrigerant port 410, first and second fluidports 420, 430, and refrigerant port 490. First major surface 450 shownin FIG. 4 is on the refrigerant side of plate W. The first and secondfluid ports 420, 430 include sealing structures 421, 431 that form aseal when contacting complementary sealing structures on an adjacentplate in the stack, thus preventing the fluid from entering therefrigerant side of plate W. There are sealing surfaces (not shown) onthe second major surface 451 of plate W around the refrigerant ports410, 490 to prevent the refrigerant from entering the fluid side ofplate W. A sealing structure 401 may also be disposed at the peripherythe first major surface 450 which mates to a sealing structure of anadjacent plate.

The first major surface 450 of the refrigerant side of plate W includesa flow field 440 comprising numerous flow features 445, 446. The flowfeatures 445, 446 include ridges 445 and valleys 445 that may be formedby stamping, machining, molding, embossing, etching and/or otherfabrication processes. The second major surface 451 includescomplementary flow features to those disposed on the first major surface450. The flow features 445, 446 are depicted in this example as upwardpointing chevrons, however a variety of feature shapes maybe used. Theflow features 445, 446 on the first major surface 450 and thecomplementary flow features on the second major surface 451 areconfigured to direct the flow of fluid across the surfaces 450, 451,respectively, and/or to increase heat transfer area and mixing in thefluid flow. Refrigerant flows from refrigerant port 410 and condenses onthe flow features 445, 446. The condensate exits via refrigerant port490.

FIG. 5 illustrates a second type of plate (Plate Type X) that can beused in the condensation component of an adsorbent chiller subassembly.Plate X alternates with plate W in the stack that forms the condensationcomponent of the adsorption chiller subassembly. Plate X includes afirst major surface 550 and a second major surface 551. Plate X includesrefrigerant ports 510, 590, and first and second fluid ports 520, 530. Asealing structure 501 is disposed on the periphery of surface 550. Thesealing structure 501 is configured to mate with a sealing structure ofan adjacent plate in the stack. Surface 550 is the fluid side of plateX. The refrigerant port 510 and refrigerant port 590 include sealingstructures 511, 591 at the peripheries of the refrigerant port 510 andrefrigerant port 590, respectively. The sealing structures 511, 591 areconfigured to mate with complementary sealing structures at therefrigerant ports of the next plate in the stack to prevent therefrigerant vapor and/or condensate from interacting with fluid side(surface 550) of plate X. Plate X includes a flow field 540 on surface550 which has flow features 545, 546 depicted in this example asdownward pointing chevrons. Note that flow features 545 and 546 appearas ridges and valleys, respectively, on surface 550. Complementary flowfeatures (not shown) appear on second major surface 551. Water, e.g.,room temperature water flows through flow features 545, 546 on thesurface 550 between fluid ports 520 and 530.

The W and X plates may alternate in the plate stack so that thedirection of the chevrons of the W plates opposes the direction of thechevrons of the X plates. As previously mentioned, orienting the platesso that the chevron features of adjacent plates touch in a lattice ofcontact points creates numerous flow paths, increasing the heat transferarea and mixing in the flow.

FIGS. 6 and 7 illustrate type Y and type Z plates, respectively, thatmay be used in the adsorbent component of the adsorption chillersubassembly. As illustrated in FIG. 6, the type Y plate has a firstmajor surface 650 and a second major surface 651. At least some of thefeatures of the first major surface 650 are complementary to thefeatures of the second major surface 651. A sealing ridge 601 isdisposed along the periphery of the first major surface 650. The sealingstructure 601 is designed to mate with a corresponding sealing structureof an adjacent plate in the stack. The Y plate includes first and secondrefrigerant ports 610, 620 and first and second fluid ports 630, 640.Sealing structures 611, 621 are disposed along the periphery of therefrigerant ports 610, 620. The Y plate includes a flow field 660 havingflow features 665, 666 arranged in this example in a two dimensionalchevron pattern. The chevron ridges 665 on surface 650 appear as chevronvalleys on surface 651 and the chevron valleys 666 on surface 650 appearas chevron ridges on surface 651.

FIG. 7 depicts a type Z plate that may alternate with the Y plate in theplate stack forming the adsorption component of the adsorption chillersubassembly. The Z plate includes a first major surface 750 and a secondmajor surface 751. The first major surface 750 of plate Z has a flowfield 760 with flow features 765, 766 which may be arranged in a twodimensional chevron pattern as shown in FIG. 7. Complementary flowfeatures (not shown) are located at the second major surface 751.Adsorbent 771 is disposed in an adsorbent bed 770 on the first majorsurface 750. The adsorbent 771 may be located in, on and/or around theflow features 765, 766. For example, the adsorbent 771 may comprisesilica gel beads or silica gel in some other form, and/or otheradsorbent material. The adsorbent 771 is arranged in the adsorbent bed770 so that refrigerant vapor ingress and egress from the adsorbent ispromoted. The adsorbent bed 770 may include surface features, e.g.,protrusions and/or indentations in the surface which serve to increasethe exposed surface area of the adsorbent and promote interactionbetween the adsorbent and the refrigerant vapor. In this example, theflow features 765 are interrupted with spacers 767 which space the flowfeatures on surface 750 apart from the flow features of an adjacentplate in the stack to facilitate better vapor flow between the adjacentplates.

FIG. 8 conceptually illustrates a see through view of a two plate stackcomprising a Y plate and a Z plate. Features of the Y plate are shown insolid lines and features of the Z plate are shown in dashed lines. Thepattern of flow features of the Y and Z plates are opposing such theflow feature pattern of the Y plate includes upward pointing chevrons,whereas the flow feature pattern of the Z plate includes downwardpointing chevrons. The opposing flow feature pattern promotes fluidmixing which facilitates heat transfer, and increases heat transferarea.

FIG. 9 shows a side view of an example of adsorption chiller subassembly900, which includes an arrangement of plates, such as the platesdescribed in connection with FIGS. 2 through 8. As previously mentioned,in some implementations, an adsorption chiller may include twosubassemblies 900, so that a first portion of adsorbent in the firstsubassembly (e.g., silica gel) can be regenerated in a regenerationphase at the same time that a second portion of adsorbent material in asecond subassembly is being saturated in a cooling phase.

The condensation component 910 of subassembly 900 may include multiplestacked plates having alternating type W and type X plate configurationsillustrated in FIGS. 4 and 5, respectively. The evaporation component920 may include alternating type U and V plates as illustrated in FIGS.2 and 3, respectively. The adsorbent component 930 is arranged betweenthe condensation component 910 and the evaporation component 920. Theadsorbent component 930 may include multiple stacked plates having the Yand Z plate configurations illustrated in FIGS. 6 through 8. Some or allof the plates of the adsorption chiller subassembly 900 may be attachedto a neighboring plate, e.g., by welding, brazing, gasketing, orotherwise sealing one plate to another. Additionally, or alternatively,the alignment of the plates in the stack may be maintained and/or theplates in the stack may be compressed using one or more threaded tierods and nuts, not shown. The sealing process used to seal plate pairsmay be selected to contain vapor and/or fluids at pressures used in theadsorption chilling process, e.g., the sealing is sufficient to achievethe near vacuum pressures that produce boiling water at close to roomtemperatures in the refrigerant portions of the chiller.

The dashed lines in FIG. 9 illustrate first and second refrigerantchannels 940, 950 formed by the refrigerant ports of the stacked plates.During the evaporation phase, water vapor is created in the evaporationcomponent 920 and travels along a path indicated by arrow 970 throughthe first refrigerant channel 940 to the adsorption component 930. Inthe adsorption component 930, during the cooling phase, the water vaporis adsorbed by the silica gel (or other adsorbent) that is disposed inthe adsorbent beds of the plates of the adsorption component 930.

During the regeneration phase, water vapor is released from the silicagel in the adsorbent bed of the adsorption component 930 and travelsalong a path indicated by arrow 980 through the second refrigerantchannel 950 to the condensation component 910. Before the evaporationphase the condensed water is returned from the condensation component tothe evaporation component through fluid return 960. In general, endplates (not shown in FIG. 9) are used to contain the stack components.

FIG. 10 conceptually illustrates a possible arrangement of plates of theadsorbent chiller subassembly 900 of FIG. 9. It is to be understood thatFIG. 10 illustrates one possible arrangement of plates, although manyother arrangements and/or plate designs are also possible. For example,plates having various flow features other than those illustrated hereinmay be used in place of or in addition to the illustrated chevronfeatures.

When arranged in the stack, each of the plates U, V, W, X, Y, Z includesa refrigerant side and a fluid side. When adjacent plates in the stackare attached together, the refrigerant sides of adjacent plates face oneanother and the fluid sides of adjacent plates face one another. Thespaces between the refrigerant sides of the adjacent plates formrefrigerant passages and the spaces between the fluid sides of theadjacent plate form fluid passages.

In this example, the evaporation component 920 includes alternating Uand V plates, as illustrated in FIGS. 2 and 3. Each of the type U andtype V plates are oriented with the refrigerant ports at the top. Therefrigerant ports of each type U and type V plates are aligned to formthe first refrigerant channel 940 which fluidically connects theevaporation component 920 and the adsorption component 930. The U and Vplates are arranged in the evaporation component 920 so that therefrigerant sides of each of the U and V plates face each other. Each ofthe UV pairs defines a refrigerant passage between the front surface ofa U plate (the refrigerant side of the U plate), and the back surface ofa V plate (the refrigerant side of the V plate). The fluid sides ofadjacent V and U face each other and the facing fluid sides of each VUpair defines a fluid passage, e.g., room temperature water passagebetween the V and U plates.

The adsorption component 930 of subassembly 900 comprises a stack ofalternating Y and Z plates as depicted, for example, in FIGS. 6 through8. The Y and Z plates are arranged in the adsorption component 930 sothe refrigerant sides of adjacent Y and Z plates face each other and therefrigerant sides of Y and Z plates in each of the YZ pairs defines arefrigerant passage between the Y and Z plates with an adsorbent beddisposed in the refrigerant passage. The fluid sides face each other andthe fluid sides of each adjacent Z and Y plates of each ZY pair definesa fluid passage, e.g., a passage for RT water between the Z and Y platesduring the cooling phase and for heated water during the regenerationphase.

The condensation component 910 of the adsorption chiller subassembly 900includes type X plates that alternate with type W plates. Therefrigerant ports of the X and W plates are aligned to form the secondrefrigerant channel 950 which fluidically connects the condensationcomponent 910 and the adsorption component 930. The X and W plates arearranged in the condensation component 710 so that the refrigerant sidesof X and W plates face each other the refrigerant sides of each of theXW pairs defines a refrigerant passage between the X and W plates. Thefluid sides of W and X plate face each other and define a fluid passage,e.g., a passage for RT water flow, between the W and X plates.

As discussed in connection with FIG. 7, the type Z plate includesspacers that space the refrigerant side of a type Z plate apart from theadjacent Y plate. Consequently the distance, d2, between the refrigerantsides of the Y and Z plates in a YZ pair may be greater than thedistance, d1, between the fluid sides of the Z and Y plates in a ZYplate.

The components of the adsorption chiller subassembly may be arranged ina number of configurations. FIG. 11 illustrates another possibleconfiguration of an adsorption chiller subassembly 1100. The subassembly1100 includes a condensation component 1110, and evaporation component1120 and an adsorbent component 1130 arranged between the condensationcomponent 1110 and the evaporation component 1120. In thisconfiguration, the condensation component 1110 of subassembly 1100 mayinclude multiple stacked W and X plates as illustrated in FIGS. 4 and 5.The evaporation component 1120 may include alternating type U and Vplates. The adsorbent component 1130 may use modified versions of Y andZ plates. In the illustrated configuration, the upper refrigerant portof plates Y and Z is not needed and may be eliminated. The condensation1110, evaporation 1120, and adsorption 1130 components can befluidically coupled through a single refrigerant channel 1140.

During the cooling phase, water vapor from evaporation component 1120travels along a path indicated by arrow 1170 through the refrigerantchannel 1140 to the adsorption component 1130. In the adsorptioncomponent 1130, during the cooling phase, the water vapor is adsorbed bythe silica gel that is disposed in the adsorbent beds of the plates ofthe adsorption component 1130.

During the regeneration phase, water vapor is released form the silicagel in the adsorbent bed of the adsorption component 1130 and travelsalong a path indicated by arrow 1180 through the second refrigerantchannel 1140 to the condensation component 1110. The condensed water isreturned from the condensation component to the evaporation componentthrough fluid return 1160.

In some embodiments, the plates used in the adsorption component mayhave flow features that surround the refrigerant port, as illustrated byplates S and T shown in FIGS. 12 and 13, respectively. FIG. 12 shows atype S plate that includes a first major surface 1250 at the fluid sideof the plate, and a second major surface 1251 at the refrigerant side ofthe plate. A sealing structure is disposed along the periphery of thefirst major surface, which mates with an adjacent plate in the stack.

The type S plate includes two fluid ports 1210, 1230 and a refrigerantport 1220. The refrigerant port 1220 includes a sealing structure 1221at the periphery of the refrigerant port 1220. The sealing structure1221 mates with the fluid side of the adjacent plate in the stack andprevents refrigerant from entering the fluid passage.

The S plate includes a flow field 1240 having flow features 1245, 1246which surround the refrigerant port 1220. The flow features compriseridges 1245 and valleys 1246 on the first major surface 1251.Complementary flow features (not shown) are disposed on the second majorsurface 1251.

In some implementations, T plates, shown in FIG. 13, alternate with Splates in the adsorption component. The type T plate has a first majorsurface 1350 at the refrigerant side of the plate, and a second majorsurface 1351 at the fluid side. The T plate includes two fluid ports1310, 1330 and a refrigerant port 1320. The fluid ports 1310, 1330include sealing structures 1311, 1331, at their respective peripheries.The T plate includes a flow field 1340 which surrounds the refrigerantports 1310. The flow field includes flow features 1345, 1346. Adsorbentmaterial 1371 is disposed in an adsorbent bed 1370. For example, theadsorbent 1371 may be disposed in the adsorbent bed 1370 in, on, and/oraround the flow features 1345, 1346. The T plate includes spacers 1375configured to space apart the refrigerant sides of adjacent plates tofacilitate the flow of refrigerant through the refrigerant passages. Thespacers 1375 are only an example of one type of feature which may beincluded to promote the transmission of refrigerant vapor to theadsorbent. In other cases, other features may be present. For example,the adsorbent may be arranged in stripes or other patterns withinterpenetrating vapor channels. These refrigerant passages may beramified, interconnected in a network, etc. depending on the arrangementof the adsorbent and refrigerant port or ports.

FIG. 14 illustrates a possible configuration of an adsorption chillersubassembly 1400 that uses the S and T plates in the adsorptioncomponent. The subassembly 1400 includes a condensation component 1410,and evaporation component 1420 and an adsorbent component 1430 arrangedbetween the condensation component 1410 and the evaporation component1420. The condensation component 1410 may include multiple stacked W andX plates as illustrated in FIGS. 4 and 5. The evaporation component 1420may include alternating type U and V plates as illustrated in FIGS. 2and 3. The adsorbent component 1430 may use alternating S and T plates.The condensation 1410, evaporation 1420, and adsorption 1430 componentscan be fluidically coupled through a single refrigerant channel 1440.The design illustrated in FIG. 14 removes the need for a fluid returnfor returning the condensate to the evaporation component that isexternal to the plates.

Some embodiments involve plate designs that can be stacked together forma monolithic subassembly that performs the functions of an adsorptionchiller. In these embodiments, the evaporation, condensation, andadsorbent components are not defined by separate stacks of plates, e.g.,as depicted in FIG. 9. The plates in the monolithic subassembly can havea more complex structure, as illustrated in the exploded view of theadsorption chiller subassembly 1500 illustrated in FIG. 15. In thisimplementation, there are two plate configurations, denotedconfiguration A and configuration B which alternate in the stack. Eachplate includes a refrigerant side and a fluid side. The refrigerantsides of a B plate and an A plate define one refrigerant chamber whenthe outer sealing surface of the B plate seals to the next A plate inthe stack. The resulting refrigerant chamber contains all of thecomponents of the low pressure side of an adsorption chillersubassembly. Similarly, the fluid sides of adjacent A and B plates inthe stack are sealed together. Three separate fluid passages, denotedtop, middle, and bottom fluid passages, are defined between the fluidsides of adjacent A and B plates. Note that although the terms top,middle, and bottom or used in this description, these terms are onlyused to describe different sections of the plates and are not meant toimply any limitation with respect to any particular orientation of theplates. In other words, in alternative embodiments, the sectiondesignated as “bottom” may be oriented towards the top of thesubassembly, etc.

During the cooling phase, vapor is generated in the bottom section ofthe refrigerant passage, the evaporation cools the water which isflowing in the bottom fluid passage formed between the fluid sides ofthe A and B plates. The vapor created in the bottom section of therefrigerant passage formed between the refrigerant sides of the B and Aplates travels to the middle section of the refrigerant passage which isthe adsorption region. Silica gel, or other adsorbent, is disposed in,on, and/or about the flow features located at the middle section of therefrigerant passage. RT water flows in the middle fluid passage formedbetween the fluid sides of the A and B plates during the cooling phaseto keep the silica gel cool during the adsorption process.

During the regeneration phase, the silica gel is heated to drive off thewater vapor. Hot water is flowed through the middle fluid passage,heating the silica gel disposed in the middle section of the refrigerantpassage, thus forcing water vapor out of the silica gel. The water vaporthat is forced out of the silica gel travels to the upper section of therefrigerant passage and condenses. The top section of the refrigerantpassage is kept cool by flowing RT water through the top fluid passage.Condensed water collects in the tray formed by the ridge below the topsection of the refrigerant passage. The condensed water is then directedto the bottom section of the refrigerant passage by a fluid channel (notshown).

Silica gel (or other adsorbent) is placed or packed in, on and/or aboutthe flow features of the adsorbent region of the adsorbent chillersubassembly 1500. In some embodiments, the silica gel is fixed in place,for example by adhering, epoxying or brazing the silica gel to the metalplate, before the plates are stacked into the adsorption chillersubassembly.

FIGS. 16 and 17 provide a more detailed view of the B and A plates,respectively, depicted in FIG. 15. FIG. 16 shows the refrigerant side ofplate B which has a condensation section, an adsorption section, and anevaporation section. Plate B includes a first major surface 1650 whichis on the refrigerant side of the plate and a second major surface 1651which is on the fluid side of the plate. A sealing structure 1605 isdisposed along the periphery of the first major surface 1650. Fluidports 1610, 1620, 1630, 1640, 1660, 1665 include sealing structures1611, 1621, 1631, 1641, 1661, 1666 configured to mate with complementarysealing structures of an adjacent plate to form a seal that prevents thefluid from entering the refrigerant side of the plate.

The condensation region includes a flow field 1600 that includes flowfeatures 1601 a (ridges) and 1601 b (valleys), illustrated as chevronsthat point towards the right in this example. Complementary flowfeatures appear on the second major surface 1651 of the B plate.Condensed water condenses on the surface of plate B in the condensationsection and drips into the tray formed by ridge 1602. The condensedwater exits the condensation section via upper refrigerant port 1603 andis carried into the evaporation section via lower refrigerant port 1604.

The evaporation section of the B plate includes a flow field 1670 havingflow features 1671 a (ridges) and 1671 b (valleys). In thisimplementation, the flow features 1671 a and 1671 b are illustrated aschevrons pointing to the right. The condensate drips on the flowfeatures 1671 a and 1671 b and evaporates. Refrigerant vapor rises fromthe evaporation section to the adsorption section of the subassembly.The adsorption section includes a flow field 1680 having flow features1681 a (ridges) and 1681 b (valleys) which are depicted in this exampleas upward pointing chevrons. An adsorbent 1690, such as silica gel, isdisposed in, on, and/or around the flow features 1681 a,b in anadsorbent bed 1691. As the vapor from the evaporation region enters theadsorption region, the vapor is adsorbed by the adsorbent 1690.

The fluid side of plate A is illustrated in FIG. 17. Plate A includes acondensation section, an adsorption section, and an evaporation sectionthat correspond to the condensation, adsorption, and evaporationsections of plate B. Plate A includes first and second major surfaces1750, 1751. The first major surface 1750 is on the fluid side of plate Aand the second major surface 1751 is on the refrigerant side of plate A.As illustrated in FIG. 17, plate A includes a sealing structure 1705disposed along the periphery of the first major surface 1750. Thesealing structure 1705 mates with a sealing structure of the next platein the stack, e.g., a sealing structure on the second major surface of aB plate, to prevent refrigerant from entering the fluid passages. Fluidports 1710, 1720, 1730, 1740, 1760, 1766 do not include sealingstructures on the first major surface 1750 (fluid side) of plate A.Refrigerant ports 1703 and 1704 include sealing surfaces 1713 and 1714to prevent the refrigerant from interacting on the fluid side of plateA.

The condensation region includes a flow field 1700 that includes flowfeatures 1701 a (ridges) and 1701 b (valleys) illustrated as chevronsthat point towards the left in this example. RT water flows in the flowfield 1700 in a fluid passage formed between the first major surface1750 of plate A and the fluid side of an adjacent B plate. The RT watercauses the vapor in the condensation section of the refrigerant passageto condense. The fluid passage in the condensation section of plate A isseparated from the fluid passage in the adsorption section by ridge1760. In the adsorption section of plate A, water is directed across thesurface of flow field 1780 by flow features 1781 a (ridges) and 1781 b(valleys) which are shown in this example as downward pointing chevrons.RT temperature water flows across the first major surface 1750 of plateA in flow field 1780 during the adsorption phase. Hot water flows in theflow field 1780 during the regeneration phase.

The fluid passage in the adsorption section is separated from the fluidpassage in the evaporation section by ridge 1765. The evaporationsection of A plate includes a flow field 1770 having flow features 1771a (ridges) and 1771 b (valleys). In this implementation, the flowfeatures 1771 a,b are illustrated as chevrons pointing to the left. Aswater in the refrigerant passage evaporates, it chills water flowing inthe flow field 1770 of the fluid passage in the evaporation section.

FIG. 18 illustrates an arrangement of the A and B plates that form amonolithic adsorption chiller subassembly. The A and B plates alternatein the stack. Refrigerant passages are formed between the refrigerantsides of the B and A plates in the BA plate pairs. Evaporation,adsorption, and condensation fluid passages are formed between the fluidsides of the A and B plates in the AB plate pairs.

FIG. 19 is a flow diagram that illustrates a process for making anadsorption chiller subassembly including one or more plates that supportan adsorption bed. Plates including flow features on surfaces of theplates are formed 1910 by stamping, embossing, molding, machining, orother processes. A bonding material is applied 1920 to the exposedsurface of the plates in the area of the adsorbent bed. The bondingmaterial may comprise an adhesive, e.g., an epoxy, thermoset adhesive,pressure sensitive adhesive, or a braze or other bonding material. Thebonding material may be applied by application of a foil, a paste, byspraying, brushing, printing, dipping, and/or other processes. Adsorbentmaterial, such as silica gel, is affixed 1930 the surface of the plateby the bonding material. The plates are assembled 1940 in the stack inthe predetermined configuration to form the evaporation, condensation,and adsorbent regions of the chiller.

In some cases, the adsorbent may be affixed in the adsorption bed bybrazing. The brazing process can be used for plate-based adsorptionchillers as discussed herein, or for shell and tube, plate-fin, or othertypes of chillers. FIG. 20 is a flow diagram that illustrates a processfor making an adsorbent chiller that involves brazing the silica gel toplates and/or other structures that support the adsorbent bed. A brazematerial, such as an active braze material, is disposed 2010 in theregion of the adsorbent bed. In the case of plate-based chillers, theactive braze material would be disposed on the exposed surface of aplate in the adsorbent bed region of the plate. The active brazematerial may coat flow features formed in the plate surface, forexample. An exemplary list of active braze materials is provided inTable 1. The active brazing process is so denoted because there aremetals in the braze compound that are chemically active during thebrazing process. In some processes, the brazing is performed undervacuum. In the case of silica, braze materials of Ti or In, or acombination of the two, may be used. Alloys such as Cusin-1-ABA andIncusil-ABA may be used for active brazing of silica. These arerelatively low temperature braze alloys, and so are less sensitive tothe difference in thermal expansion coefficient between silica and themetal of the plates. In other cases, a higher temperature braze alloymay be desired.

TABLE 1 Nominal Composi- Liquidus Solidus Form Name tion % ° C./° F. °C./° F. Availability Gold-ABA ®-V Au—97.5 1090 1045 Wire, Foil Ni—0.75V—1.75 Gold-ABA ® Au—96.4 1030 1003 Wire, Foil Ni—3 Ti—0.6 Copper-ABA ®Cu—92.75 1024 958 Wire, Foil (L) Si—3.0 Al—2.0 Ti—2.25 Nioro ® - Au—82.0960 940 Wire, Foil ABA ™ Ni—15.5 V—1.75 Mo—0.75 Tini-60 ™ Ti—67.0 980942 Foil, Paste Ni—33.0 Ticuni ® Ti—70 960 910 Foil, Paste Ni—15 Cu—15Ticuni-60 ® Ti—60 940 890 Foil, Paste Ni—25 Cu—15 Silver-ABA ® Ag—92.75912 869 Wire, Foil, Cu—5.0 Paste AI—1.0 Ti—1.25 Ticusit ® Ag—68.8 900780 Wire, Foil, Cu—26.7 Paste Ti—4.5 Cusil-ABA ® Ag—63.0 815 780 Wire,Foil, Cu—35.25 Paste Ti—1.75 Cusin-1-ABA ® Ag—63.0 805 775 Wire, Foil,Cu—34.25 Paste Sn—1.0 Ti—1.75 Incusit ®- Ag—59.0 715 695 Wire, Foil,ABA ™ Cu—27.25 Paste In—12.5 Ti—1.25

For example, the braze material may be applied to the surface of aplate, e.g., as a foil or as a paste. The adsorbent material is applied2020 to the layer of the active braze. The braze is heated 2030 in avacuum or inert gas until it is above its liquidus temperature at whichpoint the braze flows over the surface of the plate, flowing between thesurface of the plate and the adsorbent material by capillary action. Theplate is then cooled 2140 to below the solidus temperature of the braze,thus joining the adsorbent to the structure of the adsorbent chillerthat supports the adsorbent bed.

In some cases, the braze used to affix the adsorbent to the plate mayhave liquidus and solidus temperatures that are in the same range as thebraze used to attach the plates together. In these cases, thefabrication process of FIG. 21 may be useful. A first braze material isapplied 2110 to the sealing structures of the plates. A second brazematerial, such as an active braze suitable for brazing the adsorbent isapplied 2120 to the surface of at least some of the plates in the regionof the adsorbent bed. For example, the second braze may be applied toeach plate in the adsorbent bed region or may be applied to every otherplate. The adsorbent material is applied 2130 to the layer of the secondbraze. The plates are assembled 2140 in the stack, which brings thesealing structures of the adjacent plates together, with the first brazematerial disposed between the sealing structures of the adjacent plates.The plate stack is heated 2150 to a temperature that is at or above theliquidus temperatures of both the first and second braze materials. Theplate stack is cooled 2160 to the solidus temperature of the first andsecond brazes. By this process one heating and cooling cycle may be usedto attach the plates together at the sealing structures via the firstbraze material and to attach the adsorbent to the surface of at leastsome of the plates via the second braze material.

In some implementations, the temperature of the braze used to affix theadsorbent may be different from the temperature of the braze used toattach the plates in the stack to one another, as illustrated by theflow diagram of FIG. 22. A higher temperature braze can be applied 2210to the adsorbent bed region of at least some of the plates. Theadsorbent material 2220 is applied to the higher temperature braze. Theplates are heated 2230 to the liquidus temperature of the highertemperature braze and then cooled to the solidus temperature of thebraze.

A lower temperature braze is applied 2240 to the sealing structures ofthe plates, including the plates having the adsorbent brazed thereto.The plates are assembled 2250 in a stack. The plate stack is heated 2260to the liquidus temperature of the lower temperature braze and thencooled to the solidus temperature of the lower temperature braze. Theprocess of brazing the plate stack does not disturb the attachment ofthe adsorbent to the plate because brazing the plate stack occurs at atemperature that is below the liquidus temperature of the braze used forthe adsorbent material.

In some implementations, as illustrated in FIG. 23, the attaching theadsorbent to the adsorbent region of at least some of the plates may beaccomplished by forming 2310 a paste comprising an adhesive or brazealong with the adsorbent material. For example, if a braze is used toattach the adsorbent, the paste would comprise the adsorbent and thebraze. If an adhesive such as epoxy is used to attach the adsorbent, thepaste would comprise the components of the epoxy (or other adhesive) andthe adsorbent. The paste is applied 2320 to the adsorbent bed region ofthe plates. If a braze is used (option 1), after the paste is applied,the plates are heated 2330 to the liquidus temperature of the braze andare cooled to the solidus temperature. If an adhesive is used (option2), the adhesive is cured 2340, e.g., by time, cooling, UV light and/orother curing processes. After the adsorbent is attached, the plates areassembled 2350 in the stack.

The foregoing description of various embodiments has been presented forthe purposes of illustration and description and not limitation. Theembodiments disclosed are not intended to be exhaustive or to limit thepossible implementations to the embodiments disclosed. Manymodifications and variations are possible in light of the aboveteaching.

The invention claimed is:
 1. A subassembly for an adsorption chiller,comprising: an adsorption component including: a plurality of adsorptionplates arranged in a stack; a plurality of refrigerant passages definedbetween refrigerant sides of adjacent pairs of the adsorption plates inthe stack; an adsorbent material disposed within the refrigerantpassages; and a refrigerant port disposed through each adsorption plate;a condensation component including: a plurality of condensation platesarranged in the stack; and a refrigerant port disposed through eachcondensation plate; and a evaporation component including: a pluralityof evaporation plates arranged in the stack; and refrigerant portdisposed through each evaporation plate, wherein the plurality ofadsorption plates are arranged in the stack between the plurality ofevaporation plates and the plurality of condensation plates andrefrigerant ports of the plurality of adsorption plates, the pluralityof evaporation plates and the plurality of condensation plates arealigned to form a single refrigerant channel that connects theevaporation component, the adsorption component, and the condensationcomponent so as to form a unitary structure.
 2. The subassembly of claim1, wherein a plurality of fluid passages are defined between fluid sidesof adjacent pairs of the plates in the stack.
 3. The subassembly ofclaim 1, wherein the adsorbent is attached to refrigerant sides of atleast some of the plates by an epoxy or a braze material.
 4. Thesubassembly of claim 1, wherein the adsorbent material comprises silica.5. The subassembly of claim 1, wherein the adsorbent material compriseszeolite.
 6. The subassembly of claim 1, wherein: the adsorption platescomprise a first type of plate and a second type of plate that alternatein the plate stack; the first type of plate comprises first flow fieldfeatures disposed on a refrigerant side and a fluid side of the firsttype of plate; and the second type of plate comprises second flow fieldfeatures disposed on a refrigerant side and a fluid side of the secondtype of plate, and spacers disposed on the refrigerant side of thesecond type of plate.
 7. The subassembly of claim 1, further comprising:a plurality of refrigerant passages defined between refrigerant sides ofsome adjacent pairs of the evaporation plates in the evaporationcomponent stack, wherein the refrigerant passages of the evaporationplates are fluidically coupled to the refrigerant passages of theadsorption plates.
 8. The subassembly of claim 7, further comprising: aplurality of refrigerant passages defined between refrigerant sides ofsome adjacent pairs of the condensation plates in the condensationcomponent stack, wherein the refrigerant passages of the condensationplates are fluidically coupled to the refrigerant passages of theadsorption plates and to the refrigerant passages of the evaporationplates.
 9. The subassembly of claim 8, further comprising: a pluralityof fluid passages defined between some adjacent pairs of the evaporationplates in the evaporation component stack, the fluid passagesalternating with the refrigerant passages in the evaporation componentstack; and a plurality of fluid passages defined between some adjacentpairs of the condensation plates in the condensation component stack,the fluid passages alternating with the refrigerant passages in thecondensation component stack.
 10. The subassembly of claim 1, wherein:the adsorption plates include a first type of plate and a second type ofplate, each plate having a refrigerant side and a fluid side; and therefrigerant side of each first type plate is vacuum sealed to arefrigerant side of a second type of plate to form a refrigerant chamberof the adsorption chiller subassembly.
 11. A subassembly for anadsorption chiller comprising a stack of plates, each plate having anevaporation section, an adsorption section, and a condensation section,the plates arranged in the stack so that the evaporation sections of theplates form an evaporation unit of the adsorption chiller subassembly,the adsorption sections of the plates form an adsorption unit of theadsorption chiller subassembly, and the condensation sections of theplates form a condensation unit of the adsorption chiller subassembly;and further comprising sealing structures configured to fluidicallyseparate the evaporation section, adsorption section, and condensationsection from each other.
 12. The subassembly of claim 11, whereinadsorbent material is disposed between refrigerant sides of the platesin the adsorbent section of the subassembly.
 13. The subassembly ofclaim 11, wherein: the plates include a first type of plate and a secondtype of plate, each plate having a refrigerant side and a fluid side;and the refrigerant side of each first type plate is vacuum sealed to arefrigerant side of the second type of plate to form a refrigerantchamber of the adsorption chiller subassembly.
 14. The subassembly ofclaim 13, wherein: the refrigerant side of the first type of plateincludes first evaporation flow features in the evaporation section,first adsorption flow features in the adsorption section, firstcondensation flow features in the condensation section; and furthercomprising a tray feature disposed in the condensation section andconfigured to hold condensate produced in the condensation section. 15.The subassembly of claim 13, wherein: the fluid side of the second typeof plate includes second evaporation flow features in the evaporationsection, second adsorption flow features in the adsorption section, andsecond condensation flow features in the condensation section.
 16. Amethod of forming an adsorption chiller, comprising: attaching anadsorbent on refrigerant sides of a plurality of adsorption plates;arranging the plurality of adsorption plates having the attachedadsorbent between a plurality of evaporation plates and a plurality ofcondensation plates in a plate stack; aligning refrigeration ports ofthe plurality of adsorption plates, the plurality of evaporation platesand the plurality of condensation plates to form a single refrigerantchannel that connects the plurality of evaporation plates, the pluralityof adsorption plates, and the plurality of condensation plates, forminga unitary structure.
 17. The method of claim 15, wherein attaching theadsorbent comprises: forming a paste that includes an adhesive or brazematerial and the adsorbent; and thermal cycling the braze or during theadhesive.